Apologies if this has been covered. I recently purchased a U.S. stock within my SD/RSP which accounts for about 22% of my relatively small portfolio.

My question is if I am very fortunate and the stock does well what happens if all of a sudden it accounts for 35% of my portfolio. What are the consequences? Would I have to increase my Canadian content to kep pace or is it based on my breakdown at the time of purchase.